Soprano Dame Joan Sutherland ruled the opera world for almost 40 years. She left her native Australia for London in 1951, where she worked her way up to become one of the most acclaimed sopranos of this century. Sutherland retired in 1990. Through journals and diaries she and her husband, conductor Richard Bonynge, kept track of her performances and travels in painstaking detail. Those details are the basis of her new autobiography, "A Prima Donna's Progress." Minnesota Public Radio's Tom Crann spoke with Joan Sutherland about her career, her influences, and her favorite operatic role.